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Dallas RAM
tekochip   6/8/2012 10:44:48 AM
Before FLASH memory a popular device was a battery backed RAM. Dallas made several flavors of these and they were used in all kinds of products. The RAM was potted with a battery inside so there was no way to change the battery. Naturally these parts started to fail about ten years after they were deployed, and replacing them became quite a common repair. Finding replacements is difficult and is sometimes the end of a nice piece of equipment.

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OLD_CURMUDGEON   6/7/2012 7:51:39 AM
You'll notice I linked both terms with a "/", since it is most common that in modern vehicles, the speedometer AND the odometer are one unit.  So, IF the odometer is NOT functioning correctly, then HOW does one comply with the FTC mandate for accurately recording the mileage driven?  It seems to me that you nitpicked my comments for no viable reason.

And, IF the odometer is NOT functioning correctly, then there will be further problems in the future as more & more jurisdictions are seriously considering changing the way they collect road use tax.  As vehicles become more fuel efficient, the amount of fuel dispensed will begin to taper off, and the governments' revenus streams will be seriously affected.  In some areas proposals have been advanced to base the registration / renewal / etc. fee on the annual miles driven.  In essence this will force manufacturers to provide tamper-proof odometers or similar technology to accurately secure that data.  Maybe a function of the "black boxes" being installed in new vehicles will be a record of the actual miles driven.  And, when one goes to renew their vehicle registration, it will have to be done at an "official" station, which can scan the black box for that data.

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LloydP   6/6/2012 9:11:06 PM
A functioning odometer is not required for safety in any consumer vehicle. The FTC (Federal Trade Comission) requires an odometer to:

1. Provide an accurate measure of actual miles driven, protecting a buyer against fradulant claims by a used vehilce seller.

2. Protect the manufacturer against fradulent warrenty claims based on a doctored odometer reading. 

If the odometer is incorrect or non-functional, the law can be met by placing a sticker on the doorpost indicating that the mileage shown on the odometer is incorrect. This is also the way to meet federal correct mileage regulations when a defective odometer is changed. There are no safety related requirements for an odometer.

On the other hand, as OLD_CURMUDGEON says, a functional accurate spedometer is a safety related issue.

Most passenger car and light truck applications integrate the spedometer and odometer into the "instrument cluster." This is not necessarily so for medium and heavy duty truck, bus, or RV applications. In many cases, the RV manufacturer buys a truck chassis from GM/Ford/Freightliner/etc. This chassis may include a powertrain (engine, transmission and rear differential) and, according to federal regulations, is classified as an incomplete vehicle. The final (RV) manufacturer then completes the manufacturing into a complete saleable vehicle, and is responsible for meeting all federal regulations applicable to that class of vehicle.

Owning or operating any vehicle with a non-functional or incorrect odometer is not illegal or unsafe. However, misleading a potential buyer about an odometer reading violates both federal and state laws.


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OLD_CURMUDGEON   6/6/2012 7:44:48 AM
It seems to me that the JUDICIOUS (I do not use that word lightly!) course of action should have been to solicit the aid of your state's attorney general office and/or the federal NHTSA people, since the lack of a functioning speedometer/odometer IS a moving vehicle safety-related issue.  IF state/federal pressure had been exerted on FLEETWOOD, you can bet your life that they would have found a solution to your (and others) problem of an ineffective design.  It is unconscionable to me that FLEETWOOD was not held accountable for this major error.  And, IF the Chevrolet Motor Division was in any way complicit in this, then they should also have had their feet held to the fire!

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more soldered-in batteries
Norm   6/5/2012 9:56:30 PM
I had a similar situation on my sailboat, which had a water-consumption counter driven by a flow sensor.  Branded "Amiot", it was actually a Hengstler TICO 731 LCD counter module.  When the display faded and finally died, I pulled it out to discover it had a permanently-mounted lithium cell.  Unfortunately, despite being a simple counter with no calibration as such, replacing the battery did not resurrect it. 

I found the manufacturer data sheet spec'd the instrument to have a "7-year life".  When contacted for a reset procedure, the manufacturer responded simply, "It is not intended to change the battery, it is intended to change the instrument".   I could not spending $98 for a coin cell.

Needless to say, I did not replace it with the same make/model, and instead installed a Red Lion counter powered by ship's 12V, with nonvolatile count memory when power is off.  Despite being larger and needing a fair amount of mechanical and woodwork to fit, I am much happier with the replacement. 

Boats last longer than 7 years, people.  But then, I can't imagine anything worthy of installing such a counter which wouldn't outlast the battery. 


William K.
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Monkey Made Odometer
William K.   6/5/2012 7:14:42 PM
I routinely repair things thate were intended to only be serviced as assemblies. Partly, I do this for fun, and the challenge, but also from being cheap.

So fixing the odometer with the welded in battery could be an interesting challenge, but if the program was also stored in volatile memory, that is just plain disreputable and evil.

Of course there have been other vendors of equipment that did the same thing, evidently figuring that when somebody paid a few thousand for a transciever that they werre only entitled to use it for about 6 years before it lost it's mind.

For the RV, forget getting an exact replacement since it too would be junk. There are a few aftermarket packages that should work in it's place, and not have that problem. In fact, there are may still be available an electric drive speedometer that used a remote generator and had a totally mechanical odometer and display. So there is another option. You might be able to find one of those at some auto boneyard.

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did you find a replacement ?
GlennA   6/5/2012 3:36:17 PM
You mentioned this was a Chevy chassis.  Was the drivetrain also Chevy ?  Did you find a Chevy part to fix it ?  Is it safe to assume the speedometer was independent of the odometer and still worked ?

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